I am right now in the final stages of building a large distributed peice of software in perl for enterprise use. It will be issuing an estimated 24/7 average of about 200 transactions per second to a relational database, with peaks up to double that for short periods. It will be receiving data updates from 5,000+ machines in multiple datacenters to drive these transactions. The relational database itself will be holding 1-2 TB of data, a good third of which is constantly being recycled in a matter of days. Every last little peice of code (on the 5,000+ machines, and the central server, and the midlayer between them) involved is written in perl, with the exception of some small peices of code in database trigger functions that's written in sql.
So far, it's working great.
In some ways, perl is no different than C - it can do whatever you want, as long as you code it correctly to do so.